Expressing the Future: munu, ætla, present

Here is a fact that surprises English speakers: Icelandic has no future tense. There is no ending you add to a verb to push it into the future, and there is no single auxiliary that means "will" in all cases. Instead Icelandic expresses future time with a small toolkit — most often just the present tense plus a time adverb, sometimes the auxiliary munu for predictions, and very often ætla að for intentions. The hardest adjustment for an English speaker is to stop hunting for a "will" word: in Icelandic the plain present, with a "tomorrow" or "next week" to anchor it, is usually all you need. This page maps the options and the choices between them; the full paradigms of munu and ætla live on their Verb Reference pages.

The default: present tense + time adverb

By far the commonest way to talk about the future is to use the present tense and let a time expression — á morgun "tomorrow", í kvöld "tonight", á þriðjudaginn "on Tuesday", eftir viku "in a week" — supply the future meaning. This is exactly like English "The train leaves at three" or "I'm flying to Akureyri tomorrow", except Icelandic uses it for almost any future event, not just scheduled ones.

This is the form to reach for first. If a beginner translates "I will eat later" word-for-word and goes looking for an auxiliary, they end up with something stilted; the natural Icelandic is simply Ég borða seinna "I eat later". When in doubt, use the present and add a time word.

munu + infinitive — prediction and the formal future

When you want to predict something — to say what will happen, with a flavour of certainty or forecast — Icelandic uses munu + a bare infinitive. Munu is a defective, preterite-present auxiliary: it has no real infinitive in everyday use and conjugates irregularly. Its register leans formal, written, and predictive — weather forecasts, news, planning documents, solemn promises — rather than casual chat.

Here is the paradigm — note that, like the modals, it looks alien because it is preterite-present:

Two things to notice. First, munu takes a bare infinitive — það mun rigna, never mun að rigna. Second, the past column, myndi / myndir / myndu, is the ordinary Icelandic word for "would" — the conditional auxiliary you meet in ég myndi gera það "I would do it". So munu and the conditional myndi are two faces of the same verb; the conditional has its own page.

ætla að + infinitive — intention and plans

When the future is about what someone intends or plans to do — a decision, a personal plan — the natural verb is ætla að + infinitive. Ætla is a regular weak verb (past ætlaði) and, unlike munu, it requires að before the following infinitive. This is the everyday, conversational way to announce plans, and it corresponds closely to English "going to" / "intend to".

The contrast with munu is the heart of the matter. Munu makes a prediction about how the world will turn out; ætla reports a plan that a person has formed. "It will rain" is það mun rigna (a forecast, nobody's intention); "I'm going to call her" is ég ætla að hringja í hana (your decision). You cannot say það ætlar að rigna to forecast weather, because rain has no intentions — though, idiomatically, Icelanders do sometimes personify the weather this way ("looks like it's going to rain"), which is a nice illustration of how ætla is fundamentally about intention.

verða að — the obligation-tinged future

A fourth, narrower option: verða að + infinitive, "have to / must", which often carries future force because an obligation is something to be discharged later. When you say Ég verð að fara á fundinn á morgun "I have to go to the meeting tomorrow", you are simultaneously stating an obligation and a future event. Use it when the future is driven by necessity rather than plain prediction or free intention.

How the trio carves up English "will"

This is the distinguishing insight. English crams prediction, intention, and commitment all into one word, will — "It will rain" (prediction), "I'll study Icelandic" (intention), "I will help you, I promise" (commitment). Icelandic splits these across three different auxiliaries:

Skulu (present skal) is the third corner: a firm promise, undertaking, or command — Ég skal hjálpa þér "I'll help you (you can count on it)". Choosing among the three is really choosing what kind of future you mean: a forecast (munu), a plan (ætla), or a personal guarantee (skulu). The dedicated munu vs skulu vs ætla page drills this distinction.

Common Mistakes

Don't slap munu onto every future. The default future is the present tense plus a time adverb; munu is reserved for genuine predictions and formal register.

Ætla is about intention; use munu for impersonal forecasts. (Icelanders do personify weather with ætla colloquially, but the safe, clear choice for a forecast is munu.)

Ætla is in the að camp. Don't drop the að — ætla að læra, never ætla læra.

The mirror error: munu takes the bare infinitive. Ætla needs að; munu forbids it.

When the meaning is a vow or guarantee, the idiomatic auxiliary is skulu (ég skal), not ætla and not munu.

Key Takeaways

• Icelandic has no inflected future tense; the default future is the present tense + a time adverb (ég fer á morgun).
• munu (mun, munt, mun, munum, munuð, munu) + bare infinitive marks a prediction / forecast and leans formal; its past forms myndi/myndir/myndu are the ordinary "would".
• ætla að
  • infinitive (weak, past ætlaði) marks intention / plans and is the everyday conversational future.
• verða að
  • infinitive gives an obligation-tinged future ("have to … by then").
• The munu / ætla / skulu trio splits English "will" into prediction / intention / commitment — pick the auxiliary by which kind of future you mean.